Due to the intermittent drive of the recuperator piston, hydraulic positive-displacement pumps generate pressure pulsations which, create undesirable noise.
Such pumps serve, for example, for the hydraulic fluid supply of hydraulic brake units or of hydraulic power steering assemblies in automotive vehicles. The damping device serves to reduce pulsations of the pressure and of the delivery flow. Damping devices are employed both for the purpose of noise reduction and to avoid pressure surges in the system to be operated. A pump of this kind is known from German published patent application No. 32 09 296, the damping device being, however, configurated in the shape of an additional damping chamber requiring considerable space and including a housing of its own with guiding devices incorporated therein.
In another prior-art positive-displacement pump (German printed and examined patent application No. 15 28 359) an elastic element enclosing a gas volume is positioned both in the range of the suction connection and in the range of the delivery connection for damping of the pressure pulsation. Although suction-side pressure pulsations can be damped in a satisfactory manner by the use of an enclosed compressible gas cushion since the pressure pulsations take place at a very low pressure level, no appreciable damping of pulsations can be achieved by the disclosed arrangement in the delivery range, in particular as far as high pressure pumps are concerned, since the gas cushion loses its damping capacity very rapidly as the pressure rises.